Add `nil` and `default` type support for protocols.
Fix issue with loosing ns info in `env` passed to subsequent forms.
Update identifier translator to translate private methods like -foo to _foo.
Fix defprotocol for forms without methods.
Implement aset and alength macros.
Version 0.9.0
Merge branch 'master' into experiment/protocols
If `ns` isn't present make it's 'user.wisp.
Write `defprotocol` `deftype` tests.
Write examples for protocols.
Bump version to 0.10.0